Tractor loader



K. w. KAM PERT 7 3,009,590

TRACTOR LOADER Nov. 21, 1961 7 Sheets-Sheet 1 Filed May 29, 1957 K. w. KAMPERT 3,009,590

TRACTOR LOADER Nov. 21, 1961 Filed May 29, 1957 7 Sheets-Sheet 2 INVENTOR.

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K. W. KAM PERT TRACTOR LOADER Nov. 21, 1961 7 Sheets-Sheet 5 Filed May 29, 1957 INVENTOR. @QM PW 0AM TRACTOR LOADER 7 Sheets-Sheet 6 Filed May 29, 1957 Nov. 21, 1961 K. w.. KAMPERT 3,009,590

TRACTOR LOADER Filed May 29 19 7 Sheets-Sheet 7 United States Patent 3,009,590 TRACTOR LOADER Keith W. Kampert, Libertyville, Iil., assignor to The Frank G. Hough Co., a corporation of Illinois Filed May 29, 1957, Ser. No. 662,457 17 Claims. (Cl. 214-440) This invention relates to tractor loaders, and more specifically to an improved operating and control arrangement for the bucket of a tractor loader.

One common type of tractor loader used in the art comprises a vehicle or tractor carrying a bucket fork or other tool which extends forwardly of the tractor. Generally the bucket or tool is carried on boom means, and in operating the loader, some means must be provided for tilting the bucket to various positions relative to the boom means and for holding the bucket in those various positions to provide for the various necessary loader functions such as digging, carrying and dumping of some material. Different lever and linkage systems are present'ly used in the art as a means for tilting and holding the bucket relative to the boom. These mechanical linkage systems have one important deficiency. This defioiency is that there is considerable variation in the speed of the pivoting bucket and in the torque applied to pivot the bucket due to the changing moment arms inherent in such constructions. Further, in those instances where it would be desirable that the speed of the pivoting bucket be varied by the operator no means are provided for accurately and efficiently performing this function. Additionally, due to the relatively great distance between the operator of the loader and the cutting edge of the bucket, it is oftentimes difficult for the operator to gauge exactly in what position the cutting edge of the bucket is disposed at any point in the pivoting range of the bucket.

It is the object of the present invention to provide a front end type tractor loader with means for pivoting the bucket relative to the boom wherein the torque applied to turn the bucket will be constant throughout the necessary pivoting arc of the bucket and in any position of the boom.

It is another object of the present invention to provide a front end type loader with hydraulically operated means for pivoting the bucket relative to the boom wherein for a constant hydraulic pressure the torque applied to pivot the bucket will be constant throughout the necessary pivoting arc of the bucket and in any position of the boom.

It is another object of the present invention to provide a front end type tractor loader with hydraulically operated means automatically operating to maintain the bucket in any one pivoted position relative to ground level as the boom is raised and lowered.

It is a further object of the present invention to provide a front end type tractor loader with hydraulically operated means under the control of the operator wherein the bucket may be pivoted relative to the boom at different selected speeds and wherein the bucket may be indexed in a plurality of dififerent pivoted positions relative to the boom, and additionally, wherein the hydraulically operated means will automatically operate to maintain the bucket in any indexed position relative to the boom as the boom is raised and lowered.

It is another object of the present invention to provide a front end type tractor loader with hydraulically operated means for pivoting the bucket relative to the boom wherein the torque applied to pivot the bucket will be constant throughout the entire pivoting arc of the bucket and in any raised or lowered position of the boom and wherein the speed of pivoting of the bucket relative to the boom is directly under the control of the operator 2 of the loader and wherein the operator of the loader may selectively index the bucket relative to the boom to a plurality of dififerent positions, and additionally, wherein the bucket will be automatically maintained in any one indexed position as the boom is raised and lowered.

Other objects and features of the present invention will be apparent upon a perusal of the following specification and drawings of which:

FIGURE 1 is a side elevation-a1 view of one embodiment of a tractor loader constructed according to the present invention;

FIGURE 2 is a top plan view of the structure shown in FIGURE 1;

FIGURE 3 is a side elevational view of the structure shown in FIGURE 1 with the boom means operated to raised the bucket;

FIGURE 4 is an enlarged partial plan view of the structure shown in FIGURE 1 taken along the line 4--4 of FIGURE 1;

FIGURE 5 is a partial schematic view of a portion of the hydraulic system of the present invention and a crosssectional View of a portion of the structure shown in FIGURE 4- taken along the line 5-5 0t FIGURE 4;

FIGURE 6 is a side elevational view of another embodiment of a tractor loader constructed according to the present invention;

FIGURE 7 is a side elevational View of the structure shown in FIGURE 6 with the boom means. operated to raise the bucket;

FIGURE 8 is an enlarged partial plan view of the structure shown in FIGURE 6 taken along the line 88 of FIGURE 6;

FIGURE 9 is an enlarged cross-sectional view of a portion of the structure shown in FIGURE 6 taken along the line 9-9 of FIGURE 6; and

FIGURE 10 is a schematic view of a portion of the hydraulic system of the second embodiment of the present invention combined with a portion of the bucket operating mechanism shown in FIGURE 6.

The present embodiments are the preferred embodiments, but it is to be understood that changes can be made in the present embodiments by one skilled in the art without departing from the spirit and scope of the present invention.

Generally, the instant invention comprises two embodiments. In the first embodiment a rotary hydraulic motor 10 is used for pivoting the bucket relative to the boom, in the second embodiment a pair of reciprocating hydraulic rams ll of the multi-stage type are used to pivot the bucket relative to the boom. Statements in the objects of the instant invention relating to the constant torque produced for pivoting the bucket do not apply to the second embodiment. The first embodiment comprises a tractor 12, having boom means 13 pivotally carried from the tractor and extending forwardly thereof, with the forward end of the boom means 13 carrying a double acting rotary hydraulic motor 10*, and a bucket 14, with the boom means 13, the hydraulic motor 10 and the bucket 14 operatively interconnected, and with a hydraulic valve arrangement 15 mounted between the tractor l2 and the bucket 14. The hydraulic valve arrangement 15 controls the flow of hydraulic fluid to and from the rotary hydraulic motor 19, which in turn controls pivotal position of the bucket 14 relative to the boom means 13. The location of the pivot axes at each end of the hydraulic valve arrangement 15 and at each end of the boom means 13 is such that a parallelogram is defined. The hydraulic valve arrangement 15 will operate automatically to control the operation of the hydraulic motor 10 to maintain the bucket 14 in any one pivoted position relative to the ground, and the hydraulic valve arrangement 15 is further under the direct control of the operator of the loader so that the operator may cause a pivoting of the bucket 14 at any selected speed and may further index the bucket in any one of a number of predetermined positions. The second embodiment of the present invention is similar in many respect to the first and like parts are identically numbered therein. This embodiment comprises a tractor 12, having boom means 13 pivotally carried from the tractor and extending forwardly thereof, with the boom means 13 carrying a pair of double acting hydraulic rams 11 and at the forward end thereof pivotally carrying a bucket 16, and with a hydraulic valve arrangement 15 mounted between the tractor 12 and the bucket 16. The hydraulic valve arrangement 15 controls the flow of hydraulic fluid to and from the double acting hydraulic rams 11, which in turn control the pivotal position of the bucket 16 relative to the boom means 13. The hydraulic valve arrangement 15 will automatically operate to control the operation of the hydraulic rams 11 to maintain the bucket 16 in any one pivoted position relative to ground level as the boom means 13 is raised and lowered, and the hydraulic valve arrangement 15 is further under the direct control of the operator of the loader so that the operator may control the speed at which the bucket 16 is pivoted relative to the boom 13 and so that the operator may index the buckets in any number of a plurality of predetermined positions relative to ground level. The location of the pivot axes at each end of the hydraulic valve arrangement 15 and at each end of the boom means 13 is such that a parallelogram is defined.

Turning next to the detailed description of the structure of the first embodiment of the present invention reference is made to FIGURES 1 through 5. The tractor 12 of the present embodiment is of the four wheel rubber tired type and comprises a frame member 17 mounted on the wheels 18 and carrying a rearwardly disposed engine compartment 19 and a forwardly disposed operators compartment 20.

The boom means 13 comprises a pair of boom arms positioned one on each side of the tractor 12. One end of each of the boom arms is pivotally mounted on the tractor 12 through brackets 21 and pins 22 and 23. The brackets 21 are secured one on each side of the tractor 12 and the pin 22 is journalled through the rearward end of the boom arm on the right side of the tractor 12 and secured in suitable openings in the bracket 21. The boom arm on the left side of the tractor 12 and the pin 23 are similarly mounted in cooperation with the bracket 21 mounted on that side of the tractor 12. The pin 22 is provided with an opening longitudinally therethrough. The other end of each boom arm extends forwardly of the tractor 12 and is provided with a bearing thereat. To raise and lower the boom arms, a pair of hydraulic rams 32 are provided. The head end of each hydraulic ram 24 is pivotally mounted on one side of the tractor 12 through a bracket 25 and a pin 26. The rod end of each hydraulic ram 24 is pivotally mounted to one of the boom arms intermediate the ends thereof by means of a pin 27. The boom means 13 is further provided with a brace 28 which is secured between the boom arms forwardly of the tractor 12.

The bucket 14 of the first embodiment comprises a pair of spaced apart side walls 29 interconnected by a curved plate 30 which forms the rear and bottom walls of the bucket 14-' The forward marginal edge of the bottom wall portion of the plate 30 is provided with a cutting edge 31 which extends upwardly a short distance of the side walls 29. The rear wall portion of the plate 30 is provided with a pair of depressions 32 which are spaced transversely of the bucket 14 to permit the bucket to be pivoted rearwardly a maximum amount. The rear wall of the bucket is also provided with two pairs of flanges 33 and 34. The pair of flanges 33 are spaced transversely of the bucket 14 a distance approximately equal to the distance between the boom arms. Each of the flanges 34 is spaced transversely outwardly from one of the flanges 33 a distance approximately equal to the thickness of the boom arms. Each of the boom arms is pivotally mounted at the outer end thereof between one of the flanges 33 and 34 by means of a pin 35 journalled through the bearing in the end of the boom arm, as can be seen in FIGURE 4. The boom means 13 thereby pivotally carries the bucket 14 transversely and forwardly of the tractor 12.

The double acting rotary hydraulic motor 10 may be constructed in a number of different ways. Since in the instant invention the bucket 14 need not be tilted, relative to the boom means 13, through an angle of more than approximately the hydraulic motor shown in cross section in Flf-URE 5 is suflicient for the purposes of the present invention. The hydraulic motor comprises a relatively long cylindrical casing 33, and a shaft 39 which extends longitudinally through the casing 38 and a short distance outwardly from each end. The casing 38 is formed to have two integrally formed walls 40 which extend inwardly along a diameter of the casing 13. The walls 40 extend longitudinally between each end of the casing 38. The innermost ends of the walls 40 are formed as arcuate surfaces, and the shaft 39 is positioned in cooperation with these arcuate surfaces of the walls 40. The curvature of the arcuate surfaces of the walls 40 is the same as the curvature of the shaft 39. The outwardly extending ends of the shaft 39 are splined. The portion of the shaft 39 within the casing 38 is provided with two vanes 41. The vanes 41 are formed to have a rectangular shape and are of a length substantially equal to the internal length of the casing 38 and have a width sub stantially equal to the distance between the outer surface of the shaft 39 and the inner wall of the casing 33. The vanes 41 are secured to the shaft 39 as by Welding and are positioned to extend radially outwardly therefrom along a diameter thereof. End walls are also provided for the casing 38 and these walls cooperate into the walls 41 and the ends of the vanes 41 to divide the hydraulic motor into four compartments. These compartments are defined by the casing 38, the walls 40, the shaft 39 and the vanes 41, there being no direct fluid communication between the compartments. Each of the four defined compartments of the hydraulic motor 10 is provided with a fluid port extending therefrom through the walls 40 and externally of the casing 38. The ports of diametrically opposed compartments of the hydraulic motor 10 are interconnected by fluid conduits with conduits 42 and 43 connecting one pair of diametrically opposed ccmpartments, and with conduits 44 and 45 connecting the other pair of diametrically opposed compartments. Thus it may be seen that if high pressure hydraulic fluid is delivered to conduits 42 and 43, and if conduits 44 and 45 are vented to a sump or reservoir, high pressure hydraulic fluid will enter the compartments in the hydraulic motor 10 associated with conduits 42 and 4-3 to force the vanes 41 in a counterclockwise direction as viewed in FIGURE 5, with the vented hydraulic fluid flowing out of the other compartments and through conduits 44 and 45. If high pressure hydraulic fluid is delivered to conduits 44 and 45, and if conduits 42 and 43 are vented to a reservoir, the vanes 41 will be moved in a clockwise direction, as viewed in FIGURE 5. Since the vanes 41 are secured to the shaft 39, any movement of the vanes 41 will cause a corresponding rotation of the shaft 39. Thus it may be seen that by selectively supplying hydraulic fluid to and venting hydraulic fluid from the hydraulic motor 10, the shaft 39 may be rotated relative to the casing in a clockwise or counterclockwise direction.

To mount the hydraulic motor 10 in cooperation with the bucket 14, and the boom means 13, the outwardly extending splined ends of the shaft 39 are each mounted within a splined hole in a block 47. Each of the blocks 47 is secured to one of the flanges 33 by means of fasteners 48. The blocks 47 are positioned on the flanges 33 so that the axis of rotation of the shaft 39 coincides with the axis of pivoting the bucket 14 about the pins 35. Thus it may be seen that if the casing 33 of the hydraulic motor 19 is held stationary, and the hydraulic motor is operated, the shaft 39 will rotate the blocks 47, which in turn will cause a pivoting of the bucket 14 about the pins 35, thereby causing a pivoting of the bucket 14 relative to the boom means 13.

To hold the casing 33 of the hydraulic motor 11) stationary relative to the boom means 13, a pair of links 49 is provided. The links 49 are mounted in a spaced apart relationship to each other between the bracing member 28 and the casing 38 of the rotary hydraulic motor 10. To mount the links 49 to the casing 38, two pairs of flanges 50 are provided. Each pair of flanges 50 is mounted at one end of the casing 38 to upstand therefrom and in transverse alignment with the slots 32 in the bucket 14. A pin 51 is mounted through each pair of flanges 51 and one end of one of the links 49. The other end of each link 49 is secured between another pair of flanges 52 by means of a pin 53 mounted through the flanges 52 and the ends of the link 49. The flanges 52 are mounted on the bracing member 28 in a spaced apart relationship transversely thereof. Thus it may be seen that the casing 38 of the rotary hydraulic motor 10 is maintained in one rotative position relative to the boom means 13 and that the casing 38 of the rotary hydraulic motor 10 is pivoted rearwardly with respect to ground level as the boom means 13 are raised.

To control the pivoting of the bucket 14, the hydraulic valve arrangement is provided. The hydraulic valve arrangement 15 comprises a hydraulic valve 55, three links or rods 56, 57 and 58, a spring assembly 59, a lever assembly 64 and a quadrant 6.1. The hydraulic valve 55 is shown in an enlarged partially cross sectional view in FIGURE 5, and the spring assembly 59 is shown inan enlarged cross sectional view in FIGURE 4. The lever assembly 60 is generally U-shaped, and the cross piece thereof is journalled through pin 22 and the wall of the operators compartment with one leg thereof extending generally upwardly in the operators compartment, and with the other leg thereof extending generally upwardly, outwardly from pin 22, as can be seen in FIGURES 1 and 2. The cross piece of the lever 60 thus pivots about the same axis of pivoting on the tractor 12 as the boom means 13. The portion of the lever 66 disposed in the operators compartment is formed as a hand lever and cooperates with the quadrant 61 which is secured to the side wall of the operators compartment adjacent to the lever 60. The quadrant 61 and the hand lever portion of the lever 60 are provided with cooperating detent means so that the lever 60 may be indexed in a selected plurality of rotative positions. The end of the leg portion of the lever 60 disposed outwardly of the tractor 12 is pivotally connected to one end of the link 56. The other end of the link 56 is secured to the threaded cap portion 63 of the hydraulic valve 55. The valve spool 64 of the hydraulic valve 55 is secured at its threaded outer end to one end of the link 57. The other end of the link 57 is secured to the casing portion of the spring assembly 59. The piston 65 of the spring assembly 59 is secured to one end of the link 53, and the other end of the link 58 is pivotally mounted to the rear surface of the bucket 14 by means of a flange 66 and a pin 67.

The hydraulic valve 55 comprises a valve body 67 having an annular bore 68 formed longitudinally therethrough. The annular bore 68 is provided with annular grooves 69, 76, 71, 72 and 73 spaced along the longitudinal axis thereof. Each of the annular grooves 69, 76', 71, 72 and 73 is connected to the outer surface of the valve body 67 by a separate fluid passageway formed between each annular groove and the outer surface of the valve body 67. The valve spool 64 is positioned within the annular bore 68 and has an outer diameter substantially equal to the diameter of the valve bore 68. The inner end of the valve spool 64 is formed of a reduced diameter and cooperates in a sliding engagement with a portion of the cap 63. The other end of the valve spool 64 is also formed of a reduced diameter, and a bushing member 74 is mounted about that end of the valve spool 64 and is secured to the valve body 67 in a fluid sealing relationship with the valve body 67 and the valve spool 64. The shoulders of the valve spool 64 adjacent to the reduced portions at each end thereof cooperate with the cap 63 and the bushing 74 to limit the possible longitudinal axial movement of the valve spool 64 to a certain amount. The valve spool 64 is further provided with two annular grooves 75 and 76 of a certain width and spaced apart a certain distance so that when the portion of the valve spool between the two grooves 75 and 76 is positioned in the center of the annular groove 71 there exists a small amount of direct fluid communication between annular groove 71 and annular grooves 69, 70, 72 and 73. Further, when the valve spool 64 is moved outwardly of the valve body 67, the annular groove 69' is sealed by the valve spool 64 from any fluid communication with annular groove 70, free fluid communication then exists between annular grooves 70 and 71, annular groove 72 is sealed from any fluid communication with annular groove 71, and free fluid communication exists between annular grooves 72 and 73. Additionally, when the valve spool 64 is moved inwardly of the valve body 67, free fluid communication exists between annular grooves 69 and 7t), annular groove 76 is sealed from any fluid communication with annular groove 71, free fluid communication is provided between annular grooves 71 and 72, and annular groove 72 is sealed from any fluid communication with annular groove 73 by the valve spool 64. The operation of the hydraulic valve 55 will be described below.

The spring assembly 59 which is shown in cross section in FIGURE 4 comprises a cylindrical casing having a pair of relatively stiff coiled springs 78 and 79 disposed therein in axial alignment. These coiled springs 78 and 79 are substantially identical, and each abuts one side of the piston member 65. The forces of the compressed coiled springs 78 and 79 against the end of the casing and the piston 65 maintain the piston 65 substantially at the center of the casing, and a force greater than that necessary to operate the hydraulic valve 55 is required to move the piston 65 relative to the casing of the spring assembly 59. This spring assembly 59 permits the bucket 14 to be lowered from a raised position when no hydraulic fluid is being supplied under pressure to the hydraulic valve 55. This is necessary since the hydraulic valve assembly 15 is mounted between the bucket 14 and the tractor 12, and the bucket 14 must be pivoted relative to the boom means 13 as the boom means 13 is lowered to prevent any damage to the hydraulic valve assembly 15. The hydraulic valve assembly 15 is furtherformed so that the pivot axes of the hydraulic valve assembly 15 at the pivotal connection of link 65 to lever 16 and at pin 67 substantially form a parallelogram with the pins 22 and 35 of the boom means 13, when the hydraulic valve 55 is in the neutral position shown in FIGURE 5 and when the spring assembly 59 is in its normal position as shown in FIGURE 4.

Turning next to a description of the hydraulic system of the present invention reference is agian made to FIG- URE 5. Conventional hydraulic pump, reservoir, valve and hydraulic conduit means (not shown) are provided for operating the pair of hydraulic rams 24. For operating the rotary hydraulic motor 14 a hydraulic pump 80 and a reservoir 81, shown schematically in FIGURE 5, are provided. The outlet or high pressure side of the hydraulic pump 80 is connected through conduit 82 to the passageway of the hydraulic valve 55 which is connected to the groove 71. The suction or low pressure side of the hydraulic pump 80 is connected through conduit 83 to the reservoir 81. The passageways of the hydraulic valve 55 which are connected into the annular grooves 69 and 73 are connected by conduits 84 and 35 respectively to the reservoir 81. The passageway of the hydraulic valve connected to annular groove 70 is connected through conduit 86 to conduits 42 and 4-3. The passageway of the hydraulic valve 55 connected into annular groove 72 is connected to conduits 44 and 45 through conduit 87. All of the conduits 82, 84, 85, 86 and 87 are not shown in FIGURES l, 2 and 3, as these conduits may be connected by any suitable path from the hydraulic valve 55 to the tractor 12. The only requirement for these conduits is that they have proper placement and suflicient length so that the hydraulic valve assembly 15 may assume a position such as shown in FIG- URE 3 without injury to the conduits.

Turning next to a description of the operation of the first described embodiment in order that the construction thereof may be more readily understood, reference is again made to FIGURES I through 5 of the drawings. With the hydraulic rams 24 substantially retracted, and with the U-shape lever 60 positioned in the vertical position shown in FIGURE 1, the bucket 14 is in the horizontal dig position at ground level. In this position the tractor 12 may be moved forwardly to cause the cutting edge 31 to dig into the material being worked. With the lever 60 stationary as shown in FIGURE 1, the hydraulic valve 55 is in its neutral position, and high pressure hydraulic fluid delivered to conduit 82 from the hydraulic pump 80 flows through the valve body and into annular groove 71. From annular groove 71 small amounts of hydraulic fluid will pass into the annular grooves 75 and 76 of the valve spool 64, and from these annular grooves into annular grooves 69, 79, 72 and 73 of the valve bore 68. From annular grooves 69 and 73 the hydraulic fluid will flow through conduits 84 and 85 respectively to the reservoir 81, and from annular grooves 70 and 72, the high pressure hydraulic fluid will flow through conduits 86 and 37 respectively to all compartments of the rotary hydraulic motor to maintain the rotary hydraulic motor 11) in one operated position.

From the position shown in the solid lines in FIGURE 1, the bucket 14 may be pivoted relative to the boom means 13 to other positions by movement of the lever 60, or by movement of the boom means 13 to raise and lower the bucket 14. To move the bucket 14 to the position shown in the dotted lines in FIGURE 1, the operator moves the lever 60 rearwardly to the rearward notch in the quadrant 61. As the lever 60 is moved rearwardly, the link 56 is moved to move the valve body of the valve 55 causing a relative outward movement of the valve spool 64 relative to the valve body 67. As the valve spool 64 is moved outwardly relative to the valve body 67, annular groove 69 is blocked by the valve spool 64, free fluid communication is provided between annular grooves 71 and 79 by means of annular groove 75 of the valve spool 64, annular groove 71 is blocked from any fluid communication with annular groove 72 by the valve spool 64, and free fluid communication is provided between annular grooves 72 and 73 by means of annular groove '76 of the valve spool 64. This operation of the hydraulic valve '55 will permit high pressure hydraulic fluid flowing from the pump 80 to flow through conduit 82, annular groove 71, annular groove 75, annular groove 79, fluid passageway 86, and through fluid passageways 42 and 43 to the compartments of the rotary hydraulic motor 10 associated therewith. Low pressure hydraulic fluid will flow from the compartments of the rotary hydraulic motor 10 associated with conduits 44 and 45, through these conduits, and through conduit 87, annular groove 72, annular groove 76, annular groove 73, conduit 85, to the reservoir 81. This hydraulic fluid flow in the hydraulic motor 10 will cause a counterclockwise rotation of the shaft 39 thereof, relative to the easing 38 thereof, to cause a rearward pivoting of the bucket 8 14. As the bucket 14 is pivoted rearwardly, the flange 66 will be moved, to in turn move the links 57 and 53 to move the valve spool 64 inwardly of the valve body 67 of the hydraulic valve 55. When the valve spool 64 reaches the neutral or center position, the hydraulic fluid pressures in the various compartments of the rotary hydraulic motor 10 will be equalized and the rotary hydraulic motor '10 will then stop its rotation maintaining the bucket 14 in the position to which it has been rotated.

From the rearwardly tipped bucket position shown in the dotted lines in FIGURE 1, or from any other intermediate position, the bucket 14 may be pivoted forwardly by a forward movement of the hand lever 60. As the lever 60 is moved forwardly, the link 56 will be moved to move the valve body 67 so that the valve spool 64 is moved inwardly of the valve body 67. When the valve spool 64 is moved in this direction, free fluid communication is provided between annular grooves 69 and 70 through annular groove 75, annular groove 70 is blocked from any fluid communication with annular groove 71, free fluid communication is provided between annular groove 71 and annular groove 72 through annular groove 76, and annular groove 72 is blocked from any fluid communication with annular groove 73. The following high pressure hydraulic fluid circuit is then completed: from the outlet of the pump 80, conduit 82, annular groove 71, annular groove 72, conduit 87, through conduits 44 and 45 to the compartments of the hydraulic motor 10 associated therewith. The following low pressure hydraulic fluid circuit is also completed: from the compartments of the rotary hydraulic motor 10 associated with conduits 42, and 43, conduit 86, annular groove 70, annular groove 69, conduit 84 to reservoir 81. These hydraulic fluid circuits will cause the shaft 39 of the rotary hydraulic motor 10 to be rotated in a clockwise direction as viewed in FIGURE 5 to cause a forward pivoting of the bucket with respect to the boom means 13. As the bucket 14 is pivoted forwardly, the flange 66 will move links 57 and 58 to draw the valve spool 64 outwardly of the valve body 67 of the valve 55. When the valve spool 64 reaches the center or neutral position relative to the valve body 67, the hydraulic fluid pressures in the various compartments of the rotary ram 10 will be equalized and the rotary hydraulic motor 10 will be stopped to in turn hold the bucket 14 in the position to which it has been pivoted.

From the foregoing it may seen that as the operator of the loader pivots lever 60, the rotary hydraulic motor 1% will respond by pivoting bucket 14. When the lever 60 is moved rearwardly, the bucket 14 is pivoted rearwardly, when the lever 60 is moved forwardly, the bucket 14 is pivoted forwardly. Further, it may be seen that with a constant pressure hydraulic fluid pump, the torque applied to pivot the bucket 14 will be constant throughout the entire pivoting arc of the bucket 14. Additionally, the hydraulic valve arrangement 15 will cause the bucket 14 to be pivoted at the same speed that the operator pivots the lever 60 and through the same are that the operator moves the lever 69. From a bucket position such as shown in the dotted lines in FIGURE 1, the hydraulic rams 24 may be extended to pivot the boom means 13 to raise the bucket 14 to a position such as shown in the solid lines in FIGURE 3. As the boom means 13 is moved from the position in FIGURE 1 to that shown in FIGURE 3, the bucket 14 must be pivoted forwardly with respect to the boom means 13 to maintain the bucket 14 substantially in the same position relative to ground level. This forward pivoting of the bucket 14 to maintain it in one position relative to ground level is automatically accomplished by the hydraulic valve arrangement 15. With the lever 60 cooperating with the rearwardmost notch of the quadrant 61, the bucket 14 will begin to be tipped rearwardly with respect to the ground as the hydraulic rams 24 begin to raise the boom means 13. This rearward pivoting of the bucket 14 with respect to the ground will cause the links 57 and 58 to move the valve spool 64 inwardly of the valve body 67 of the hydraulic valve '55. The previously noted hydraulic circuits which cause a forward pivoting of the bucket will be completed and the bucket 14 will be tipped forwardly with respect to the boom means 13 sufliciently to permit the hydraulic valve 55 to return to the neutral position. This action will be continuous and will result in maintaining the bucket 14 substantially in one pivoted position relative to the ground level as the boom means 13 is raised. When the boom means 13 is lowered with the bucket 14 in any one pivoted position, there is a tendency of the boom means 13 to pivot the bucket 14 forwardly with respect to ground level. This will cause the hydraulic valve arrangement 15 to be operated to condition the hydraulic valve 55 such that high pressure hydraulic fluid is delivered to and vented from the rotary hydraulic motor to cause a rearward pivoting of the bucket 14 relative to the boom means 13 to neutralize the tendency of forward pivoting by the boom means 13 with the result that the bucket 14 will remain in one pivoted position relative to ground level as the boom means 13 is lowered.

The dotted lines in FIGURE 3 show the dumped position of the bucket 14, and this position may be attained by a movement of the lever 16 to the forward notch in the quadrant 61. From the extreme positions shown in FIGURES 1 and 3, the hydraulic rams 24 and the rotary hydraulic motor 10 may be operated to cause any desired number or sequence of intermediate operations.

In summary it may be noted that the first embodiment of the present invention provides a certain loaded construction wherein a rotary hydraulic motor 10 is used to pivot the bucket 14- relative to the boom means 13 with a constant torque applied to the bucket 14 throughout the entire turning arc of the bucket 14 relative to the boom means 13 and throughout the entire range of movement of the boom means 13. Further, the hydraulic valve arrangement 15 provides a construction for the operator of the loader wherein the movement and position of the hand lever 60 is matched by the movement and position of the bucket 14. The bucket 14 will be pivoted at the same speed that the operator pivots the lever 60, and by varying the speed of pivoting of the lever 60, the speed of pivoting the bucket 14 may be varied. Additionally, the hydraulic valve arrangement 15 cooper-ates with the other elements of the loader to provide for automatic pivoting of the bucket 14 relative to the boom means 13 to maintain the bucket 14 in any one pivoted position relative to the ground level as the boom means 13 is operated to raise and lower the bucket 14.

The coiled spring assembly 59 permits the boom means 13 to be lowered in the event of a failure of the hydraulic fluid pressure. If the boom means 13 were lowered without hydraulic fluid pressure to pivot the bucket 14, the parallelogram defined by the pivot axes of the hydraulic valve arrangement 15 and the boom means 13 would be distorted and cause damage to the hydraulic valve assembly 15 unless some means was provided for changing the length of the hydraulic valve assembly 15. The coiled springs 73 and 79 of the assembly 59 will permit suificient movement of the piston 65 thereof thereby changing the length of the hydraulic valve assembly 15 and preventing any damage thereto.

Turning next to the description of the second embodiment of the present invention reference is made to FIG- URES 6 through 10 of the drawings. As noted previously like parts are designated with the same numerals. The tractor 12 is of the four wheel rubber tired type and includes the frame 17 mounted on wheels 18 and a rearwardly disposed engine compartment 19 and a forwardly disposed operator's compartment 20. The boom means 13 comprises a pair of boom arms positioned one on each side of the tractor 12. The rearward end of the boom arms are pivotally mounted to the tractor 12 by 10 means of brackets 21. The boom arm on the right side of the tractor 12 is pivotally mounted in the bracket 21 by means of a pin 22 having a hole longitudinally therethrough for the U-shaped lever 60 of the hydraulic valve arrangement 15. The hydraulic rams 24 for raising and lowering the boom means 13 are pivotally mounted at one end on the tractor 12 by means of brackets 25 and pins 26, and at the other end thereof to the boom means 13 through pivotal mounting means 27. The bucket 16 of the second embodiment is slightly different from that of the first embodiment. Similarly, it comprises a pair of spaced apart side walls 29 interconnected by a curved plate 30 forming the rear and bottom walls, however, the rearward side of the bucket 16 is provided with flanges different from those of the first embodiment. In this embodiment a relatively long vertical flange is disposed on the rear side of the bucket 16 at each side thereof. A flange 9 1 is also provided at each side of the bucket at the lower end of the flange 90 and spaced transversely therefrom a distance substantially equal to the thickness of the boom arms. A pin 92 is mounted between each pair of flanges 90 and 91 and one of the boom arms of the boom means 13 to pivotally mount the bucket 16 transversely of the tractor 12 and forwardly thereof. Each side of the bucket 16 is also provided with a flange 93 and each flange 93 is positioned at the upper end of one of the flanges 90 and spaced transversely therefrom. The bucket 16 further carries the conventional cutting edge 31.

The rod end of each double acting hydraulic ram 11 is pivotally mounted between one pair of the flanges 90 and 93 by means of a pin 94 mounted therethrough. The head end of each hydraulic ram 11 is pivotally mounted to a bracket by means of a pin 96, as can be seen in FIGURE 8. Each bracket 95 is mounted on one of the boom arms of the boom means 13 intermediate the ends thereof.

It thus may be seen that if the hydraulic rams 24 are expanded and retracted, the boom means 13 will be pivoted to raise and lower the bucket 16, and if the hydraulic rams 11 are expanded and retracted the bucket 16 will be pivoted relative to boom means .13.

The hydraulic valve arrangement 15 of the second embodiment is substantially the same as that of the first embodiment. The lever 60 is mounted in the same manner through the pin 22 and the wall of the operators compartment so that the hand lever portion is within the operators compartment and so that the other leg portion extends upwardly outwardly from the bracket 21 and is pivotally connected to one end of the link 56. The other end of the link 56 is secured to the threaded cap 63 which is secured to the valve body 67 of the hydraulic valve 55. The valve spool 64 of the valve 55 is connected to one end of link 57 and the other end of link 57 is connected to the casing portion of the coiled spring assembly 59. One end of the link 58 is connected to the piston 65 of the coiled spring assembly 59 and the other end of the link 58 is pivotally mounted to a bracket 66 by means of a pin -67. The bracket 66 is mounted on the rear wall 30 of the bucket 16. The pivot axes of the hydraulic valve assembly 15 and the boom means 13 define a parallelogram.

The hydraulic valve 55 is identical to that of the first embodiment wherein the valve spool 64 is provided with annular grooves 75 and 76, and the valve body 67 is provided with annular grooves 69, 70, 71, 72 and 73, and wherein the bushing 74 cooperates with the valve spool 64 and the valve body 67 to properly seal the hydraulic valve 55.

The spring assembly 59 which is shown in cross section in FIGURE 8 comprises a cylindrical casing having a pair of relatively stiff compressed coiled springs 78 and 79 disposed therein in axial alignment. These coiled springs abut each side of the piston member65. This assembly 59 function in substantially the same manner 11 as the spring assembly 59 previously described for the first embodiment of the present invention.

The hydraulic system of the second embodiment is substantially similar to that of the first. Conventional hydraulic pump, reservoir, valve and conduit means (not shown) are provided for operating the pair of hydraulic rams 24. For operating the hydraulic rams 11, a hydraulic pump 80 and a reservoir 81 are provided. The outlet or high pressure side of the pump 30 is connected through conduit 32 to annular groove 71 of the hydraulic valve 55. The suction or low pressure side of the hydraulic pump 80 is connected to the reservoir 81 through conduit 83. Annular grooves 69 and 73 are connected by conduits 84 and 55 respectively to the reservoir 81. Annular groove 70 of hydraulic valve 55 is connected to the rod end of hydraulic rams 11 through conduit 99, and annular groove 72 is connected to the head end of each hydraulic ram 11 through conduit 98. Although only one hydraulic ram 11 is shown in FIGURE it is intended that the conduits 98 and 99 be connected in parallel to the other hydraulic ram 11. All of the conduits 82, 84, 85, 98 and 9-9 are not shown in FIGURES 6 and 7 as these conduits may be connected by any suitable paths from the hydraulic valve 55 to the hydraulic rams 11 and the tractor 12. The only requirement for these conduits is that they have proper placement and sufiicient length so that the hydraulic valve assembly may assume a position such as shown in FIGURE 7 without injury to the conduits.

Turning next to a description of the operation of a second embodiment of the present invention in order that the construction thereof may be more readily understood, reference is again made to FIGURES 6 through 10 of the drawings. As in the first described embodiment, when the hydraulic valve 55 is in the neutral or center position such as shown in FIGURE 10, the hydraulic rams 11 are held in substantially the position to which they have been operated such as that shown in FIGURE 6, the digging position at ground level.

The bucket 16 may be pivoted rearwardly from the solid line position of FIGURE 6 to that shown in the dotted lines by a rearward movement of the lever 60. As the lever 60 is moved rearwardly, the valve spool 64 is moved outwardly relative to the valve body 67 to complete the following high pressure hydraulic fluid circuit: from the outlet side of the hydraulic pump 80, through conduit 82, annular groove 71, annular groove 75, annular groove 70, conduit 9d to the rod end of the cylinders of the hydraulic rams 11. Low pressure hydraulic fiuid will flow from the hydraulic rams 11 to the reservoir 81 through the following circuit: conduit 98, annular groove 72, annular groove 7 6, annular groove 73, and conduit 85. Thus the hydraulic rams 11 will be retracted to pivot the bucket 16 rearwardly with respect to the boom means 13. As the bucket 16 is pivoted rearwardly, the flange 66 on the bucket 16 will be moved to in turn move the links 57 and 58 to in turn move the valve spool 64' into the valve body 67 of the hydraulic valve 55. When the valve spool 64 reaches the neutral or center position relative to the valve spool 67, no further retraction of the hydraulic rams 11 will take place and the bucket 16 will be held in the rearward position to which it has been pivoted. The rearward notch on the quadrant 61 corresponds to the carry position shown in the dotted lines in FIGURE 6.

If the boom means 13 is raised by an extension of the hydraulic rams 4 when the bucket 16 is in a position such as shown in the dotted lines in FIGURE 6, it is apparent that with the bucket 16 held by the hydraulic rams 11, there is a tendency for the bucket to be pivoted rearwardly relative to ground level as it is raised. This tendency will cause an operation of the hydraulic valve 55 such that the valve spool 64 will be moved inwardly of the valve body 67. This operation of the valve 55 will complete the following high pressure hydraulic fluid circuit from the outlet of the pump 3d: conduit 82, annula-r groove 71, annular groove 76, annular groove 72, conduit 98, to the head end of the cylinders of the hydraulic rams 11. A low pressure hydraulic fluid return circuit will be completed from the rod end of the cylinders of the hydraulic rams 11 through conduit )9, annular groove 70, annular groove 75, annular groove 69, conduit 84 to the reservoir 81. These hydraulic fluid circuits will cause an extension of the hydraulic rams 11 counteracting the tendency of the bucket to be tipped rearwardly and thereby maintaining the bucket in the same pivoted position relative to ground level as the boom means 13 is operated to raise the bucket 16. At the uppermost position of the boom means 13, the bucket will have substantially the position shown in the solid lines in FIGURE 7.

To dump the bucket 16 it is merely necessary for the operator to move the lever 60 to the forwardmost notch in the quadrant 61. As the operator moves the lever 60 forwardly, the valve spool 6-1- will be moved inwardly of the valve body 67, and hydraulic fluid circuits will be completed for causing extensions of the hydraulic rams 11 sufficient to pivot the bucket 16 to the dump position shown in the dotted lines in FIGURE 7. From the dump position the bucket may be returned to the carrying position or to any desired intermediate position.

It should be noted that due to the hydraulic valve arrangement 15 and its relationship to the bucket 16, the boom means 13 and the tractor 12, the bucket 16 may be indexed in a number of different positions relative to ground level, the bucket 16 will be maintained in any pivoted position relative to ground level as the boom means 13 is raised and lowered, and the speed at which the bucket is pivoted may be varied by the operator by varying the speed at which the lever 60 is moved. The torque applied to pivot the bucket in the second embodiment of the invention as opposed to the first embodiment, will not be a constant throughout the entire turning arc of the bucket. This variance in the torque applied to pivot the bucket 16 in. the second embodiment is due to the changing moment arms as the hydraulic rams 11 are extended and retracted.

Although the hydraulic valve arrangement 15 of the present invention has been described as directly operating the rotary hydraulic motor 10 of the first embodiment and the hydraulic rams 11 of the second embodiment, it is contemplated that a pilot valve may be substituted for the hydraulic valve 55 with a suitable pilot operated hydraulic valve mounted within the tractor 12 for operating the rotary hydraulic motor 10 of the first embodiment and the hydraulic rams 11 of the second embodiment.

Having described the invention what is considered new and desired to be protected by Letters Patent is:

1. A material handling device comprising a vehicle and a material handling implement, boom means pivotally mounted between said vehicle and said material handling implement, hydraulically operated means carried by said boom means and connected to said material handling implement for pivoting said material handling implement relative to said boom means, and hydraulic valve means comprising a manually operable lever carried on said vehicle, link means pivotally connected between said lever and said material handling implement, and a hydraulic valve connected in said link means so that said valve is operated by any force tending to change the length of said link means, and hydraulic fluid means connected between said hydraulic valve and said hydraulically operated means whereby said hydraulically operated means is operated responsive to operations of said hydraulic valve.

2. In a material handling device as claimed in claim 1 wherein the pivot axes of said boom means to said 13 vehicle and to said material handling implement, and the pivot axes of said link means to said lever and to said material handling implement, define a parallelogram.

3. In a material handling device as claimed in claim 1, wherein said hydraulic valve is formed so that said hydraulic valve operates responsive to "a lengthening of said link means to deliver hydraulic fluid to said hydraulically operated means to operate said hydraulically operated means to pivot s-aid material handling implement rearwardly, and so that said hydraulic valve operates responsive to a shortening of said link means to deliver hydraulic fluid to said hydraulically operated means to operate said hydraulically operated means to pivot said material handling implement forwardly.

4. In a material handling device as claimed in claim 1 wherein said hydraulically operated means comprises a double acting rotary hydraulic motor, said rotary hydraulic motor comprising a cylindrical casing portion and a rotatable shaft extending from each end of said casing portion, said cylindrical casing portion carried on said boom means and each end of said shaft connected to said material handling implement for pivoting said material handling implement relative to said boom means.

5. In a tractor loader as claimed in claim 1 wherein said hydraulically operated means comprises a double acting hydraulic ram, said double acting hydraulic ram pivotally mounted between said boom means and said material handling implement.

6. A material handling device comprising a vehicle and a material handling implement, a pair of boom arms, means pivotally mounting each of said boom arms at one end thereof on said vehicle, means pivotally mounting said material handling implement on the other end of each of said boom arms, hydraulically operated means carried by said boom arms and connected to said material handling implement for pivoting said material handling implement relative to said boom arms, hydraulic valve means comp-rising a manually operable lever pivotally carried on said vehicle, link means pivotally connected between said lever and said material handling implement, and a hydraulic valve connected in said link means so that said valve is operated by any force tending to change the length of said link means, and hydraulic fluid means connected between said hydraulic valve and said hy draulically operated means so that said hydraulically operated means is operated responsive to operations of said hydraulic valve.

7. In a material handling device as claimed in claim 6 wherein said hydraulically operated means comprises a double acting rotary hydraulic motor, said rotary hydraulic motor comprising a cylindrical casing portion and a rotatable shaft extending from each end thereof, said cylindrical casing portion mounted between said boom arms, and means connecting each end of said shaft to said material handling device.

8. In a material handling device as claimed in claim 6 wherein said hydraulically operated means comprises a pair of double acting hydraulic rams, each of said hydraulic rams being pivotally mounted between one of said boom arms and said material handling implement.

9. In a material handling device as claimed in claim 6 wherein the pivot axes of said boom arms to said vehicle and to said material handling implement, and the pivot axes of said link means to said lever and to said material handling implement, define a parallelogram.

10. In a material handling device as claimed in claim 6 wherein said hydraulic valve is formed so that said hydraulic valve operates responsive to a lengthening of said link means to deliver hydraulic fluid to said hydraulically operated means to operate said hydraulically operated means to pivot said material handling implement rearwardly, and so that said hydraulic valve operates responsive to a shortening of said link means to deliver hydraulic fluid to said hydraulically operated 14 means to pivot said material handling implement forwardly with respect to said boom arms.

11. In a tractor loader, a bucket, boom means pivotally carrying said bucket from said tractor, said boom means pivotally mounted to said tractor so that said bucket is raised and lowered relative to the ground when said boom means is pivoted, hydraulically operated means for pivoting said bucket, said hydraulically operated means carried by said boom means and connected to said bucket for pivoting said bucket, hydraulic valve means comprising a manually operable lever carried on said tractor, link means pivotally connected between said lever and said bucket and a hydraulic valve connected in said link means so that said valve is operated by any force tending to change the length of said link means, and hydraulic fluid means connected between said hydraulic valve and said hydraulically operated means so that said hydraulically operated means is operated responsive to operations of said hydraulic valve.

12. In a tractor loader as claimed in claim 11, wherein the pivotal axes of said boom means on said tractor and to said bucket, and the pivot axes of said link means to said lever and to said bucket define a parallelogram.

13. In a tractor loader as claimed in claim 11, wherein said link means is formed so that said bucket is. pivoted forwardly by lengthening of said link means and rearwardly by shortening of said link means, and wherein said hydraulic valve is formed so that said hydraulic valve operates responsive to a lengthening of said link means to deliver hydraulic fluid to said hydraulically operated means to operate said hydraulically operated means to pivot said bucket rearwardly and so that said valve operates responsive to a shortening of said link means to deliver hydraulic fluid to said hydraulically operated means to operate said hydraulically operated means to pivot said bucket forwardly.

14. In a tractor loader as claimed in claim 11, wherein said hydraulically operated means comprises a double acting rotary hydraulic motor, said rotary hydraulic motor comprising a cylindrical casing portion and a rotatable shaft extending from each end of said casing portion, said cylindrical casing portion carried on said boom means and each end of said shaft connectedto said bucket for pivoting said bucket relative to said boom means.

15. In a tractor loader as claimed in claim 11, wherein said hydraulically operated means comprises a double acting hydraulic ram, said double acting hydraulic ram pivotally mounted between said boom means and said bucket.

16. A material handling device comprising a vehicle, a material handling implement, means connected to said vehicle and pivotally carrying said implement thereon, means for pivoting said implement in either direction about its axis of pivoting comprising a double acting rotary hydraulic motor mounted between said first means and said implement in a position wherein the axis of rotation of said rotary hydraulic motor coincides with the axis of pivoting of said implement on said first means for directly pivoting said implement in either direction about its axis of a pivoting responsive to the operation of said rotary hydraulic motor, and a hydraulic valve arrangement mounted between said vehicle and said material handling implement, said hydraulic valve arrangement comprising a lever pivotally mounted on said vehicle and linkage means pivotally mounted between said lever and said material handling device, said linkage means including a hydraulic valve so that said hydraulic valve is operated by any change in length of said link means, and hydraulic conduit means connected between said hydraulic valve and said rotary hydraulic motor.

17. In a tractor loader, means for pivotally carrying a bucket from the forward end of said tractor, means for pivoting said bucket about an axis transversely of said tractor at a constant speed and a constant torque, said last creasing and decreasing changes in length of said linkage means.

References Cited in the file of this patent UNITED STATES PATENTS Shippee June 15, 1943 Gorsuch Apr. 1, 1947 Walstrom Jan. 17, 1956 Wagner Oct. 29, 1957 

